3D Application and Game Development ® With OpenGL java.sun.com/javaone/sf Daniel Petersen Kenneth Russell Sun Microsystems, Inc. 1 | 2004 JavaOneSM Conference | Session TS-1361 Presentation Goal Show how to build leading-edge 3D applications and games using the Java™ programming language and the OpenGL® 3D API 2 | 2004 JavaOneSM Conference | Session TS-1361 Agenda Introduction JSR Update Using JOGL With AWT and Swing Techniques for Application Development Optimizing JOGL Applications Demos Conclusion 3 | 2004 JavaOneSM Conference | Session TS-1361 Agenda Introduction JSR Update Using JOGL With AWT and Swing Techniques for Application Development Optimizing JOGL Applications Demos Conclusion 4 | 2004 JavaOneSM Conference | Session TS-1361 Introduction • OpenGL ─ Powerful, cross-platform 3D API ─ Industry standard for writing 3D applications and games ─On multiple platforms ─From multiple programming languages ─ Supported by multiple vendors ─ Provides access to latest hardware features ─Vertex and fragment programs ─Floating-point framebuffers 5 | 2004 JavaOneSM Conference | Session TS-1361 Introduction Java programming language OpenGL bindings • A few bindings under active development • LWJGL ─ Game-focused OpenGL binding ─ Single window ─ Usually full-screen • JOGL ─ Integrates with AWT and Swing • Relies on J2SE™ platform for, e.g., full-screen support • Today’s talk will use JOGL for examples 6 | 2004 JavaOneSM Conference | Session TS-1361 Introduction Java programming language OpenGL bindings • Standardization effort underway • One Java programming language binding to OpenGL ─ Can be implemented by multiple vendors if desired ─ Being developed under the Java Community ProcessSM service ─ JSRs 231 and 239 7 | 2004 JavaOneSM Conference | Session TS-1361 Agenda Introduction JSR Update Using JOGL With AWT and Swing Techniques for Application Development Optimizing JOGL Applications Demos Conclusion 8 | 2004 JavaOneSM Conference | Session TS-1361 JSR Update Overview • What are JSR 231 and JSR 239 • Benefits of a JSR • JSR 231 and JSR 239 Status 9 | 2004 JavaOneSM Conference | Session TS-1361 JSR 231 and 239 What they are • JSR 231 ─ Java bindings to OpenGL ─ Based on JOGL project on java.net ─ Most likely based on OpenGL 1.5 • JSR 239 ─ Java bindings to OpenGL ES ─ Will use the GlueGen technology of JOGL to generate bindings ─ Most likely based on OpenGL ES 1.0 • Both being run under the Java Community Process version 2.6 10 | 2004 JavaOneSM Conference | Session TS-1361 Why Do a JSR? Benefits of a JSR • Align market around one specification ─ No need to download multiple APIs for the same binding ─ Specification and TCK ensure compliant bindings can be produced ─ Ensure all functionality of native library present • Some industries (e.g., mobile devices) prefer JCP APIs 11 | 2004 JavaOneSM Conference | Session TS-1361 JSR 231 and 239 Status • Both JSRs were filed and approved by their respective ECs • Both Expert Groups have been formed and are meeting regularly • EGs working together to make both APIs as similar as possible • Both EGs hope to have EDRs late this year 12 | 2004 JavaOneSM Conference | Session TS-1361 JSR 231 and 239 Notes • Both JSRs are fundamentally tracking a third-party API • Want to track the OpenGL APIs as closely as possible • Plan to use maintenance releases for updates ─ 30-day review period (shortest possible) 13 | 2004 JavaOneSM Conference | Session TS-1361 What You Can Do More help is ALWAYS welcome • Join an Expert Group ─ Specification work ─ SI work ─ TCK work • Contribute to JOGL project on java.net • Participate in EDRs 14 | 2004 JavaOneSM Conference | Session TS-1361 Agenda Introduction JSR Update Using JOGL With AWT and Swing Techniques for Application Development Optimizing JOGL Applications Demos Conclusion 15 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing DirectDraw incompatibilies on Windows • -Dsun.java2d.noddraw=true • Disables Java 2D™ API’s internal use of DirectDraw APIs on Windows ─ Incompatible with OpenGL ─ Frequent driver bugs arise when mixing the two APIs, even when they are used in separate windows • Should be specified for all JOGL applications! ─ No harm specifying on non-Windows platforms ─ Especially for Java Web Start applications ─ Add following to resources section of JNLP file: ─ <property name="sun.java2d.noddraw" value="true"/> 16 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing GLCanvas and GLJPanel • GLCanvas: heavyweight AWT widget for OpenGL rendering ─ Best performance (hardware accelerated) ─ Works in most GUI situations ─ See this article on mixing lightweight and heavyweight widgets successfully: http://java.sun.com/products/jfc/tsc/articles/mixing/ • JPopupMenu. setLightweightPopupEnabled(false); ─ To get Swing menus to overlap GLCanvas 17 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing GLCanvas and GLJPanel • GLJPanel: lightweight Swing widget for complete compatibility with Swing UIs ─ JInternalFrames • Currently not hardware-accelerated ─ Poor performance • Investigating using OpenGL pbuffers to implement GLJPanel ─ Faster, but still not fast enough ─ Still has texture readback • Experimental work underway to integrate better with Java 2D API and “JFC/Swing” 18 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing Rendering and animation options • Automatic redraws initiated by the AWT ─ For static scenes • Call repaint() in animation thread • Use Animator class or start your own thread and call GLDrawable.display() directly ─ Most efficient for games ─ Allows optimized OpenGL context handling on some platforms ─As efficient as single-threaded C code 19 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing Multithreading • AWT events like mouse and keyboard events are delivered on AWT event queue thread • Not allowed / possible to make OpenGL calls directly inside these listeners ─ Though you can schedule or force a redraw • Instead, pass information between these threads and any animation threads via member data ─ Use appropriate synchronization ─ Read data exactly once in your display() method ─ Avoids flickering and other artifacts during mouse interaction 20 | 2004 JavaOneSM Conference | Session TS-1361 Using JOGL With AWT and Swing Examples • See demos at http://jogl-demos.dev.java.net/ for examples of animation, interaction, and advanced features 21 | 2004 JavaOneSM Conference | Session TS-1361 Agenda Introduction JSR Update Using JOGL With AWT and Swing Techniques for Application Development ─ Scene graphs and game engines ─ Object picking ─ Shadows Optimizing JOGL Applications Demos ConcSM lusion 22 | 2004 JavaOne Conference | Session TS-1361 Scene Graphs and Game Engines Overview • Higher-level, typically object-oriented layer for applications to build on top of • Often have hierarchical structure ─ Good for representing character animation • Use OpenGL or similar API at the bottom ─ Ones discussed here use JOGL • Look for extensibility ─ Ability to call out to OpenGL from within scene graph to implement leading-edge effects 23 | 2004 JavaOneSM Conference | Session TS-1361 Scene Graphs and Game Engines Examples • Xith3D: http://www.xith.org/ ─ General-purpose scene graph, but focused on gaming and high performance ─ Designed to be nearly identical to Java 3D™ APIs ─ Supports leading-edge functionality like shadow volumes and vertex and fragment programs • Aviatrix3D: http://aviatrix3d.j3d.org/ ─ Focused on visualization market ─ Minimal API design ─ Also supports vertex and fragment programs 24 | 2004 JavaOneSM Conference | Session TS-1361 Scene Graphs and Game Engines Examples • OpenMind: http://www.mind2machine.com/ ─ 3D game engine ─ Built-in support for 3D Studio Max ASE format ─ Supplies tool chain for developers 25 | 2004 JavaOneSM Conference | Session TS-1361 Scene Graphs and Game Engines Demo • Abdul Bezrati (a.k.a. “Java Cool Dude”) ─ Xith3D demos ─ http://xith.org/demo/JavaCoolDude.php 26 | 2004 JavaOneSM Conference | Session TS-1361 Object Picking Using the selection buffer • Interactive applications require the ability to pick objects in 3D • OpenGL provides a built-in mechanism for object selection ─ Special rendering mode • User supplies storage for results and sets up special “pick” matrix ─ View volume centered around cursor • Any objects rendered into this view volume are reported to the user 27 | 2004 JavaOneSM Conference | Session TS-1361 Object Picking Using the selection buffer • Set up selection buffer ─ IntBuffer buf = BufferUtils.newIntBuffer(1024); gl.glSelectBuffer(buf.capacity(), buf); • Switch into selection mode ─ gl.glRenderMode(GL.GL_SELECT); ─ Color buffer is frozen at this point and not updated until selection mode is exited • Initialize name stack ─ gl.glInitNames(); • Set up pick matrix ─ glu.gluPickMatrix(...); 28 | 2004 JavaOneSM Conference | Session TS-1361 Object Picking Using the selection buffer • Render objects, assigning names to them ─ int objectId = ...; gl.glPushName(objectId); renderObject(gl); gl.glPopName(); • Switch out of selection mode ─ int numHits = gl.glRenderMode(GL.GL_RENDER); • Process hits ─ int idx = 0; while (idx < numHits) { int hit = buf.get(idx++); ... } 29 | 2004 JavaOneSM Conference | Session TS-1361 Object Picking Demo • Selection buffer demo (courtesy Thomas Bladh) ─ http://www.sm.luth.se/csee/courses/smd/159/ TestPrograms/Picking.java 30 | 2004 JavaOneSM Conference | Session TS-1361 Object Picking Using the selection buffer • Advantages ─ Easy to